Final answer:
Setting a backfire is a firefighting technique involving the controlled burning of fuel in the path of an oncoming wildfire to create a firebreak.
Step-by-step explanation:
Setting a backfire is a strategy used in wildland firefighting where a controlled fire is deliberately lit by firefighters in the path of an oncoming wildfire. The idea behind this tactic is that the backfire will consume the available fuel (such as dry vegetation) and effectively create a firebreak, which is an area devoid of fuel that can stop or slow the spread of the wildfire. It's a dynamic and risky strategy that requires proper planning and execution to ensure that the backfire does not escape control and exacerbate the situation.